1) Total count. Some reg's recognize two of these - one for kids and eyes (to to 500/ml or g) and another for general products (up to 1000 cfu/ml or g. Major industry works at 100 cfu/ml or g.
2) Objectionable microbes. For health concerns, no detection of Staphylococcus aureus, Pseudomonas aeruginosa or Candida albicans is universal. Some reg's add Enterococcus. Many add Burkholderia cepacia complex. Major cosmetic companies specify no staph or candida as above and no detected Gram negative bacteria.